We have been interested in the relationship between oxidative stress and DJ-1, a rare cause of recessive Parkinson's disease, for several years and have focussed the relationship between oxidative stress and mitochondrial localization. Most narrowly, we have examined the role of Cysteine 106 in human DJ-1 which appears to act as a sensor for oxidative stress. Recently, we have gone back to this question because of literature data that suggests that mutation of C106 changes DJ-1 from a dimer to a monomer, promoting recruitment to mitochondria. In our experiments, we found that while we could reproduce the reported effects using chemical cross-linking, using a range of orthologous techniques showed us that this was not due to changes in dimer formation. Rather, mutations at C106 change dynamics of DJ-1 that influence cross-linking ability. These results suggest new ways in which to use chemical cross-linkers to infer protein dynamics in cells. We have also begun to characterize a mouse model of accelerated aging that may be helpful in understanding the role of DJ-1 in vivo in the future. We find that mutations in the mitochondrial polymerase gamma, which acts as a proofreading enzyme for mitochondrial DNA, causes defects in mitochondrial complex I that we identified using a proteomics approach. We infer that disassembled complex I are likely to leach electrons, leading to oxidative stress.